Such a method and such a device are disclosed in German Patent No. DE 36 25 091 (corresponding to U.S. Pat. No. 4,951,188). There, an output stage is proposed in a bridge circuit with four switching elements, the current through the load, which is arranged in the diagonal path of the bridge, being detected and compared with predetermined threshold values. If the current through the load exceeds a predetermined maximum value, then a short circuit in the region of the load is assumed, and the output stage is therefore switched off. This procedure results in the output stage being switched off even in the case of brief disturbances. The availability of the device is thus limited.
The output stages are preferably selected, in particular for economic reasons, such that the current through the load during typical functional sequences is less than the selected current limit, but in special cases the limit can be reached. If there is a corresponding reaction in such a special case and the load is disconnected, then two undesirable effects can occur, in particular in the case of idle speed controllers. One of these is that the desired function, for example the idle speed regulation, is no longer carried out. Furthermore, consequential damage can occur, in particular destruction of or damage to the controller.